Transmission belt

Abstract

A transmission belt which has a portion possessing tensile strength that consists solely of a thin, flat strip (sheathing) and that contains no reinforcing cord or cable. This strip comprises at least two thin, superposed layers bonded together and consisting of a flexible elastomer or plastomer matrix reinforced with irregular, elongated fibrils dispersed in the matrix with a dominant orientation in the longitudinal direction of the strip such that the strip has a tensile strength of at least 20 kg/cm 2 with 1% elongation.

What is claimed is: 
     
       1. A transmission belt, having a portion possessing tensile strength that consists solely of a thin, flat strip with no other reinforcing cord or cable, characterized in that said strip comprises at least two thin, superposed layers bonded together and composed of a flexible elastomer or plastomer matrix reinforced with irregular elongated fibrils dispersed in the matrix with a dominant orientation in the longitudinal direction of the strip such that this strip has a tensile strength of at least 20 kg/cm 2  with 1% elongation. 
     
     
       2. A transmission belt as claimed in claim 1, wherein the flexible elastomer or plastomer matrix is reinforced with at least 5% by weight of elongated fibrils consisting of a crystalline polyolefin having a high molecular weight which is equal or greater than 500,000. 
     
     
       3. A transmission belt as claimed in claim 2, wherein the reinforcing fibrils of the thin superposed layers are oriented in symmetrical dominant directions forming low angles of less than 10° with respect to the longitudinal direction of the strip. 
     
     
       4. A transmission belt as claimed in claim 2 in which the superposed layers are bonded together through the intermediary of a thin elastomer or plastomer connecting layer containing no reinforcing fibrils. 
     
     
       5. A transmission belt as claimed in claim 2, which is in the form of a thin, flat endless transmission belt. 
     
     
       6. A belt as claimed in claim 2, wherein the portion possessing tensile strength is bonded to an elastomer or plastomer base having a trapezoidal section, a multiple V-shaped section or a denticulated section to allow said belt to cooperate with grooved pulleys or denticulated pulleys. 
     
     
       7. A transmission belt as claimed in claim 1, wherein the reinforcing fibrils of the thin superposed layers are oriented in symmetrical dominant directions forming low angles of less than 10° with respect to the longitudinal direction of the strip. 
     
     
       8. A transmission belt as claimed in claim 7 in which the superposed layers are bonded together through the intermediary of a thin elastomer or plastomer connecting layer containing no reinforcing fibrils. 
     
     
       9. A transmission belt as claimed in claim 7, which is in the form of a thin, flat endless transmission belt. 
     
     
       10. A belt as claimed in claim 7, wherein the portion possessing tensile strength is bonded to an elastomer or plastomer base having a trapezoidal section, a multiple V-shaped section or a denticulated section to allow said belt to cooperate with grooved pulleys or denticulated pulleys. 
     
     
       11. A transmission belt as claimed in one of the claim 1 claims in which the superposed layers are bonded together through the intermediary of a thin elastomer or plastomer connecting layer containing no reinforcing fibrils. 
     
     
       12. A transmission belt as claimed in claim 11, which is in the form of a thin, flat endless transmission belt. 
     
     
       13. A belt as claimed in claim 11, wherein the portion possessing tensile strength is bonded to an elastomer or plastomer base having a trapezoidal section, a multiple V-shaped section or a denticulated section to allow said belt to cooperate with grooved pulleys or denticulated pulleys. 
     
     
       14. A belt as claimed in claim 1, which is in the form of a thin, flat endless transmission belt. 
     
     
       15. A belt as claimed claim 1, wherein the portion possessing tensile strength is bonded to an elastomer or plastomer base having a trapezoidal section, a multiple V-shaped section or a denticulated section to allow said belt to cooperate with grooved pulleys or denticulated pulleys.